Effects of short term administration of recombinant human growth hormone to elderly people.
We evaluated the effects of recombinant human GH (rhGH) in 16 men and women more than 60 yr of age. After 10 days of dietary equilibration and control collections, subjects were randomly assigned to receive 0.03, 0.06, or 0.12 mg/kg rhGH by daily injection for 7 days. A brisk rise in circulating somatomedin-C (insulin-like growth factor-I) occurred in all subjects, and this rise was dose dependent. rhGH produced striking changes in nitrogen retention, sodium excretion, and the parathyroid-vitamin D axis. Twenty-four-hour urinary nitrogen excretion decreased from 8.00 +/- 0.33 to 5.01 +/- 0.33 g (P less than 0.001), and sodium excretion decreased from 45.9 +/- 2.96 to 21.2 +/- 3.48 mmol/day (P less than 0.001). Serum calcium concentrations did not change, but serum inorganic phosphorus levels of 1.08 +/- 0.04 mmol/L at baseline increased significantly after rhGH treatment to 1.33 +/- 0.04 mmol/L (P less than 0.001). Increases were also observed in circulating PTH (53.2 +/- 6 vs. 39.5 +/- 4.2 ng/L; P less than 0.01) and calcitriol (82.8 vs. 65.8 pmol/L; P less than 0.05). A rise in serum osteocalcin (10.3 +/- .86 vs. 8.0 +/- 0.5 micrograms/L; P less than 0.05) was accompanied by increased urinary excretion of hydroxyproline (628 +/- 63 vs. 406 +/- 44 mumol/day; P less than 0.01). Despite the reduction in sodium excretion, marked increases were observed in urinary calcium (6.04 +/- 0.97 vs. 3.27 +/- 0.40 mmol/day; P less than 0.01). rhGH significantly impaired oral glucose tolerance and reduced insulin sensitivity, but was otherwise well tolerated and produced no systematic changes in weight or blood pressure. The results of this study indicate that rhGH requires further study as a potential agent for attenuating or reversing the loss of muscle and bone in elderly people.
Marcus
R
R
Aging Study Unit, Veterans Administration Medical Center, Palo Alto, California 94034.
Butterfield
G
G
Holloway
L
L
Gilliland
L
L
Baylink
D J
DJ
Hintz
R L
RL
Sherman
B M
BM
D000367:Age Factors; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D005951:Glucose Tolerance Test; D013006:Growth Hormone / Q000008:administration & dosage* / Q000378:metabolism / Q000493:pharmacokinetics; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism; D007668:Kidney / Q000187:drug effects / Q000502:physiology; D050356:Lipid Metabolism; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D015675:Osteocalcin / Q000378:metabolism; D010280:Parathyroid Glands / Q000378:metabolism; D010281:Parathyroid Hormone / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics; D012964:Sodium / Q000378:metabolism; D014807:Vitamin D / Q000378:metabolism
D010281:Parathyroid Hormone; D011994:Recombinant Proteins; D015675:Osteocalcin; D014807:Vitamin D; D010758:Phosphorus; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D012964:Sodium; D009584:Nitrogen; D002118:Calcium